In a medium size saucepan, melt the butter or margarine. Stir inthe flour to form a roux. Add the milk all at once, and whisk gentlyto blend. Over medium heat, continue to stir until slightly thickened.Add the cheese gradually, stirring until smooth. Add dry mustard(or 1 tbsp. prepared mustard) and Tabasco sauce. Stir in cookedmacaroni. The dish can be eaten after the addition of the macaroni,or if desired, pour into a 1 1/2 quart casserole dish, top withshredded cheese and bread crumbs, then bake for 25 minutes at 350degrees. Serves 4 1/2 cup servings.